Or, there might be some other trigger. Perhaps a Hezbollah attack that draws Israeli retaliation and then Iranian intervention, or Israel and Iran clashing over Syria. Or, just misperception and miscalculation. Either way, it would not take much for Tel Aviv and Tehran to engage in combat.

Should hostilities erupt, Iran will have to confront one of the most capable militaries in the world. Here are five Israeli weapons that should worry Iran:

F-35 Stealth Aircraft

Israel has bought 19 F-35s, which are scheduled to begin arriving in 2017. There are actually two what-ifs regarding the expensive and controversial U.S. stealth strike aircraft. The first is whether the F-35 will prove to be an immensely powerful weapon, or an overpriced, unreliable aircraft that will devour huge chunks of the American and Israeli budgets.

Even if the engines don't catch on fire or the aircraft's stealth design can avoid radar detection, the F-35 is not an awesome bomb carrier: to preserve stealth, it has to forego external weapons and carry just two 2,000-pound JDAM guided bombs in its internal bomb bay.

Yet the F-35's capabilities are actually the smaller what-if. The bigger question isn't what the F-35 can do, but rather what Iran thinks it can do. If the U.S. and Israel can't be sure how effective the F-35 is, then neither can Iran. In which case, they will have to assume that Israel possesses a cutting-edge stealth aircraft that can penetrate Iranian air defenses undetected and strike nuclear facilities with precision-guided weapons.

Of course, bombing Sudan is much easier than bombing Iran, which has a fairly sophisticated air defense system. But Israel's Ra'ams are a powerful weapon that would be in the forefront of any Israeli attack on Iran.

Jericho III Missiles

While Iranian missiles have received all the attention, it is worth remembering that Israel also has ballistic missiles of its own. The three-stage Jericho III reportedly can lob a 2.2-ton warhead intermediate-range ballistic missile capable of carrying a 1,000-kg (2,204-lb.) warhead more than 3,000 miles. A solid-fueled missile, which should enable it to be launched quickly if needed, the Jericho III almost certainly can carry one of the nuclear warheads that Israel has never admitted to possessing.

Such missiles, or at least those carrying conventional warheads, probably aren't accurate enough to destroy a pinpoint target like a nuclear weapons research facility. Israel would also be reluctant to launch a missile barrage for fear of international backlash, unless the situation were really critical, such as Iran firing WMDs. Still, in addition to a potent threat from Israeli aircraft, Tehran also has to reckon with powerful Israeli missiles.

In addition to their formidable capabilities as anti-surface and anti-submarine vessels, these Israeli subs are widely considered to be equipped with nuclear-armed cruise missiles. They may not be as sophisticated as U.S. or British nuclear subs with Trident missiles. But on the other hand, it's not like Iran has much in the way of anti-submarine warfare capability, let alone the capacity to deploy it in the Eastern Mediterranean or the Red Sea, from where Israeli subs could operate close to Israeli waters while still remaining within firing range of Iran. Much like U.S. missile subs, the Dolphins give Israel a second-strike capability to retaliate with nuclear weapons, even if a surprise attack on the tiny nation were to destroy Israel's other nuclear arms.

But this is only part of the equation. Just as in the Cold War, uncertainty is everything in nuclear deterrence. While Iran could undoubtedly overwhelm Israeli missile defenses by firing enough rockets, the Arrow system means Tehran can't be sure how many missiles would get through, or which targets would or would not be hit. The effect may be more psychological than physical (no less for providing psychological reassurance to the Israeli public), but it is still significant.